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Manual 4x4 disconnect

4K views 39 replies 16 participants last post by  Arcticjeep 
#1 ·
Finally got my manual axle disconnect installed, now I need to get dirty. Happy 4th jeeperz.
 

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#13 ·
Mine is mounted in the center of the dash, just above the shifters. It looks like this one would get in the way while I was getting in or out. Mine is lifted with no kind of step, I already have a tough enough time getting in it.
 
#9 ·
Thanks for the opinion. But if one developed a vacuum leak on the trail, one can lose 4wd capabilities. And hitting it with your knee will not unlock it. You have to press the button and push or pull. Every single person I've talked too on the trail that has one of these. Have had nothing but praise. And no problems. I feel better knowing that sticks and or branches won't pull on vacuum lines at the axle.
 
#11 ·
I agree the vacuum cad system is a poor design , I have a Posi-Lock and have no issues with it. My knee never gets close to it and when you lock it in it stays in. The vacuum system can be problematic with high mileage vehicles with lower vacuum readings and brittle vacuum lines. As far as gimmick goes I feel that is the way they should have built it in the first place or equipped it with locking hubs.
 
#12 ·
Being new to this jeep thing so what you are saying when you shift into 4 wheel drive vacuum causes the fork to lock the front axles to ensure both front wheels are locked together . So if i installed the cable version when I shift the shifter into 4 wheel drive I engage cable and it locks or posi the axles the same way
 
#14 ·
Being new to this jeep thing so what you are saying when you shift into 4 wheel drive vacuum causes the fork to lock the front axles to ensure both front wheels are locked together . So if i installed the cable version when I shift the shifter into 4 wheel drive I engage cable and it locks or posi the axles the same way
The posi lock is not a locking differential. Its just a manual cable actuation of the Central Axle Disconnect (CAD).
There is a persistent myth about the automatic vacuum actuation being a weak or unreliable system and the posi lok is touted as the fix.

In reality the posi lock systems have weaknesses, but they get subjected to choice-supportive bias.



 
#15 ·
To be fair, every system has flaws. But what it's about, is the least amount of trouble when your on the trail. In alot of people's opinions the cable is a better way to go. And others say there is nothing wrong with the vacuum switch. Just remember to go with what YOU think is best for you and your jeep. There will always be naysayers, but I prefer the cable.
 
#17 ·
In theory, couldn't you do the TJ axel swap, and then add some manual hubs to achieve the best of both worlds? Free spinning in front when in 2wd, and no CAD at all?

Or are manual hubs for these particular front axles non-existent in the aftermarket world?
 
#18 ·
I'd sooner cover the hole with a plate and install a 1 piece shaft... make it like the old CJs were.

All my old 4x4s had Warn Hubs but I'd engage them in the fall and free them in the spring. they claimed the disconnect gave better gas mileage but I could never measure a difference. On a YJ I see no need to disconnect. Even if it is a DD.
 
#20 ·
so get it balanced

even if it only vibrates while off roading anything mechanical out of balance eventually explodes.

but in 25 years of driving F250s I never experienced a driveshaft vibration.
 
#21 ·
Install was a breeze, just had to drill one hole through the firewall for the cable. Came with everything, but keep your old bolts, or get new ones. As it did not come with new bolts. Re-use the original fork, or you can get an upgraded fork. I have yet to put it too the test, but this weekend is my birthday. And i plan on going too bundy hill in Michigan. So I'll let y'all know how it holds up.
 
#26 ·
Working with manual steering (NO POWER), the TJ mod would make it not fun. I had 4x4 switch failure so CAD stayed locked for a bit. Steering was very difficult. I imagine that is what TJ mod would feel like in my case. That's where I though WARN manual hubs could make it doable.
Just thinking out loud.
 
#27 ·
That's where I though WARN manual hubs could make it doable.
Just thinking out loud.
The design of the unit bearing hubs make this impossible. You need to retrofit earlier cj knuckles/hubs and axles to mount old school warn hubs. They make kits for the trucks. $$$$$
 
#32 ·
My 91 YJ 4x4 is not working....Had it on a lift to check CAD (how you can accurately do this on the ground is beyond me) - Found nothing unusual, same with under hood all seems correct. Did not have vac gauge to check for vac, however there was vac at manifold...Now to replace the diaphragm at the axle housing, disassembly is required, then taking the diaphragm apart is an issue, as its not meant to be disassembled. At this stage your already at 1/2 of the posi lock installation. Why not go posi lock and be over with it.... Sure CAD was great when the Jeep was brand new, but 27 years later ? Too many vinyl hoses, connectors, crud build up internally, and even if you get it working would you bet your life it will be there when you need it??? I just don't use my 4X4 enough to keep the system alive....My gut tells me if you don't engage it frequently it won't work when you need it...I'm going with posi lock.... As a side bar, How reliable will start stop technology be in 27 years ??? That 60k Grand Cherokee will be toast while all the YJ's are rolling.....end rant.....
 
#33 ·
So I ordered a posi lock cable because the PO had the CAD apart as it was not working all the time or consistent according to him. I asked him about it and all he said was He took it off and futzed with and reinstalled it the way it came off. Problem I found was that it is installed upside down or reversed. So I think that it is just always engaged.

So my thought is instead of fixing it just get the cable and be done with it.

Another idea I have is I’m going to install a lunch box locker up front which will be great off road but not so much on road in snowy conditions. So my thinking is that I can manually disengage the CAD while on road effectively having 3 wheel drive eliminating the dangers of a locked front axle. Not sure how well it will work but that’s my idea. And this would be a rare situation.

Anyone tried this?
 
#34 ·
You guys realize this thread was 3 years old.

03marauderman, no I would not bet my life on the 2wd system that’s referred to as 4wd...it’s not really 4wd, it 50% power to one wheel in the front and the other 50% to one rear wheel when we’re talking about open differentials...which brings me to vmxwinn, how are you effectively getting 3wd, are you locked in the rear?
 
#39 ·
TruTrac Torsen limited slip in the rear axle.
 
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#35 ·
Well there are so many threads on this topic I just took a stab on this one...Actually in everything I read, you are the only one I found (although there maybe others) that refers to this as a 1/2 4x4 ? Now I know why the phrase of being 1/2 pregnant is used....Not sure if I'm off base here but, why all the effort to change the front axles to the later model ones if the rear is still only one wheel drive? I've had many Cherokee's over the years with my 88 & 94 being brand new, and never had an issue with the 4 wheel drive. This 91 YJ is a whole other issue.....You just validated my reason to go with the posi lock, not worth the effort changing the front axles.....Thanks for enlightening me....
 
#36 ·
My stock cad works flawlessly... I have replaced the servo, vacuum switch, and fork once but just for preventative maintenance..... my yj has 280,000 miles on it.....

As far as being an old thread, unless you are specifically replying to the original poster's question you should generally be starting a new thread for your own question.

Welcome to the forum.
 
#37 ·
Oh and it absolutely IS 4wd...... although that argument has nothing at all to do w the cad and posi lock does nothing to change it.

With stock open diffs front and rear driveshafts spin at the same speed and torque goes equally to the right and left from each end.... the problem comes if you don't have traction on one front and one rear...... then it becomes no wheel drive not 2 wheel drive.... a little skilled use of the brake pedal goes a long way in that instance.... or lockers send the torque to the wheels with traction.
 
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